Enable mercator-to-screen projection in GLSL

With this change, all the geo-to-screen conversion,
and the triangulation operations for geo polylines
and geo polygon are performed either at set time
or in the shader.
A separate bounding box geometry is processed
in the old way to provide a correct QtQuick Item
geometry, that can be used for nesting mouse areas,
performing translations, input event delivery, etc.

With this approach, performance are improved by more
than one order of magnitude in average, but complex
geometries will of course benefit more.

It also adds correct rendering support for polygons
with holes, previously only rendered correctly
by the MapboxGL plugin.

The polyline shader has basic miter joins. The miter is
skipped if the angle is too sharp to avoid complicating
the implementation.
This shader introduces some glitches when the polyline
is minified, for which the real fix is to
have LOD for the geometry, and render simplified
geometries at low zoom levels (added in a subsequent patch).

Note: this approach, at least in its current implementation,
does not support enabling layers on individual items, only
on the Map element.

Task-number: QTBUG-49303
Task-number: QTBUG-38459
Change-Id: I0c2dc0bf364d32f74ca7c4014f6d66e6219c8ae4
Reviewed-by: Alexandru Croitor <alexandru.croitor@qt.io>

1 files changed, 34 insertions, 57 deletions

diff --git a/src/location/declarativemaps/qdeclarativepolygonmapitem_p.h b/src/location/declarativemaps/qdeclarativepolygonmapitem_p.h
index 810a8d35..efc1a137 100644
--- a/src/location/declarativemaps/qdeclarativepolygonmapitem_p.h
+++ b/src/location/declarativemaps/qdeclarativepolygonmapitem_p.h
@@ -51,44 +51,29 @@
 #include <QtLocation/private/qlocationglobal_p.h>
 #include <QtLocation/private/qdeclarativegeomapitembase_p.h>
 #include <QtLocation/private/qdeclarativepolylinemapitem_p.h>
-#include <QtLocation/private/qgeomapitemgeometry_p.h>
 #include <QtPositioning/qgeopolygon.h>
 
-#include <QSGGeometryNode>
-#include <QSGFlatColorMaterial>
-
 QT_BEGIN_NAMESPACE
 
-class MapPolygonNode;
-
-class Q_LOCATION_PRIVATE_EXPORT QGeoMapPolygonGeometry : public QGeoMapItemGeometry
-{
-public:
-    QGeoMapPolygonGeometry();
-
-    inline void setAssumeSimple(bool value) { assumeSimple_ = value; }
-
-    void updateSourcePoints(const QGeoMap &map,
-                            const QList<QDoubleVector2D> &path);
-
-    void updateScreenPoints(const QGeoMap &map, qreal strokeWidth = 0.0);
-
-protected:
-    QPainterPath srcPath_;
-    bool assumeSimple_;
-};
-
+class QDeclarativePolygonMapItemPrivate;
 class Q_LOCATION_PRIVATE_EXPORT QDeclarativePolygonMapItem : public QDeclarativeGeoMapItemBase
 {
     Q_OBJECT
+    Q_ENUMS(Backend)
 
     Q_PROPERTY(QJSValue path READ path WRITE setPath NOTIFY pathChanged)
     Q_PROPERTY(QColor color READ color WRITE setColor NOTIFY colorChanged)
     Q_PROPERTY(QDeclarativeMapLineProperties *border READ border CONSTANT)
+    Q_PROPERTY(Backend backend READ backend WRITE setBackend NOTIFY backendChanged REVISION 15)
 
 public:
-    explicit QDeclarativePolygonMapItem(QQuickItem *parent = 0);
-    ~QDeclarativePolygonMapItem();
+    enum Backend {
+        Software = 0,
+        OpenGL = 1
+    };
+
+    explicit QDeclarativePolygonMapItem(QQuickItem *parent = nullptr);
+    ~QDeclarativePolygonMapItem() override;
 
     virtual void setMap(QDeclarativeGeoMap *quickMap, QGeoMap *map) override;
     //from QuickItem
@@ -105,6 +90,9 @@ public:
 
     QDeclarativeMapLineProperties *border();
 
+    Backend backend() const;
+    void setBackend(Backend b);
+
     bool contains(const QPointF &point) const override;
     const QGeoShape &geoShape() const override;
     void setGeoShape(const QGeoShape &shape) override;
@@ -112,45 +100,34 @@ public:
 Q_SIGNALS:
     void pathChanged();
     void colorChanged(const QColor &color);
-
-protected:
-    void geometryChanged(const QRectF &newGeometry, const QRectF &oldGeometry) override;
-    void updatePolish() override;
+    void backendChanged();
 
 protected Q_SLOTS:
     void markSourceDirtyAndUpdate();
+    void onLinePropertiesChanged();
     virtual void afterViewportChanged(const QGeoMapViewportChangeEvent &event) override;
 
-private:
-    void regenerateCache();
-    void updateCache();
-
-    QGeoPolygon geopath_;
-    QList<QDoubleVector2D> geopathProjected_;
-    QDeclarativeMapLineProperties border_;
-    QColor color_;
-    bool dirtyMaterial_;
-    QGeoMapPolygonGeometry geometry_;
-    QGeoMapPolylineGeometry borderGeometry_;
-    bool updatingGeometry_;
-};
-
-//////////////////////////////////////////////////////////////////////
-
-class Q_LOCATION_PRIVATE_EXPORT MapPolygonNode : public MapItemGeometryNode
-{
+protected:
+    void geometryChanged(const QRectF &newGeometry, const QRectF &oldGeometry) override;
+    void updatePolish() override;
+    void setMaterialDirty() override;
 
+#ifdef QT_LOCATION_DEBUG
 public:
-    MapPolygonNode();
-    ~MapPolygonNode() override;
-
-    void update(const QColor &fillColor, const QColor &borderColor,
-                const QGeoMapItemGeometry *fillShape,
-                const QGeoMapItemGeometry *borderShape);
-private:
-    QSGFlatColorMaterial fill_material_;
-    MapPolylineNode *border_;
-    QSGGeometry geometry_;
+#endif
+    QGeoPolygon m_geopoly;
+    QDeclarativeMapLineProperties m_border;
+    QColor m_color;
+    Backend m_backend = Software;
+    bool m_dirtyMaterial;
+//    bool m_dirtyGeometry = false;
+    bool m_updatingGeometry;
+
+    QScopedPointer<QDeclarativePolygonMapItemPrivate> m_d;
+
+    friend class QDeclarativePolygonMapItemPrivate;
+    friend class QDeclarativePolygonMapItemPrivateCPU;
+    friend class QDeclarativePolygonMapItemPrivateOpenGL;
 };
 
 QT_END_NAMESPACE